Tube socket



Nov. 14, 1950 w. 1. KELLY ET AL TUBE SOCKET Original Filed Nov. 10, 1943FIG. 4

INVENTOR JOHN RLIVINGOOD a WILLIAM LKELLY Hffornj Patented Nov. 14, 1950TUBE SOCKET William I. Kelly, Quakertown, Pa and John. R; Livingood,White Plains, N. Y., assignors tothe United States of America as.represented by the Secretary of War Continuation. of application Serial.No; 509,674,

This; application; May 28, 1948, Serial No. 29,865

2 Claims- (Cl. 173 -328) (Granted under the act of March 3', 1883, asamended April 30, 1928; 370 O.'G. 757) November 1943.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to us ofany royalty thereon.

The present application is a continuation of our pending application,Serial Number 509,674, filed on November 10, 1943, now abandoned.

This invention relates to sockets for electron tubes, and particularlyto a novel design of such sockets to prevent shock injury to theelectron tubes.

A conventional electron tube with a glass envelope has a plurality ofelectrode terminals or pins protruding therefrom. It is common practiceto bring these terminals, or a majority of them, out at the base of theenvelope and to i'nsort them in a more or less rigid socket, eachterminal or pin fitting into an individual insert or pinclip of saidsocket. The individual insert provides the proper contact for aparticular electrode terminal, and the tube is physically supported bythe electrode terminalswhich are inserted in thesocket.

The electrode terminals or pins of such tubes are sealed in the glass atthe base of the tube, and any pressure on them sets up strains in thglass envelope. We have found that such strains are caused by forcesapplied on the tube by inserting or-removingv thepins from the sockets,or bysubjecting the tubes to vibration or shock when properly mounted insuch sockets. Tube breakage, caused by the above-described strains, hasbeenthe source of considerable failure in electrical circuits,particularly in portable and. vehicular radio sets.

It is an object of our invention to furnish a tube socket which willeliminate; or reduce the strain:

producing forces on: the glass-envelope when'the. tube-is subjected to amaximum amountr'of excursion For a better understanding: of ourinvention together with further objects, reference is .hadi

in'the. following. description to: the: accompanying drawings Figure 1is a perspective view of ourrinvention assembled: and ready: for: use

Figure 2 is a perspective ViHWi oiour invention with' the: excursionlimiter; and. a, socket: or: base:

2 portion shown separately beforebeing assembled together;

Figure 3 is'atop view of the socket of Figure 1; Figure 3A is anenlarged fragmentary view of.

one of the pin clips of Figure 3, in position inv the socket;

Figure 4 is a sectional view of the socket taken alongline 4-4 of Figure3 and Figure 5 is an elevational view of an individual.

pin clip.

Referring to the figures, inwhich like numbers refer to like elements,the excursion limiter I is. higher than conventional shield bases, beinginch high in a preferred embodiment of our'invention as adapted to aminiature seven pin tube. This excursion limiter I is fastened to socketor base portion 2 by crimping the lower edge 3 of the excursion limiterunder the shoulder 4 of said socket portion 2. Outwardly extendingprotuberances 5 on the excursion limiter I are provided for the purposeof attaching a conventional electrical shield thereto. Notch 6 in thetop of the excursion limiter I facilitates the orientation of a.

ing material provided with proper cavities I, re-

ceivable to individual pin clips 8. A socket portion 2 for use with thesmaller, high frequency tubes may be provided with a tube 9 ofconductive material extending through a hole I [I at the center of thesocket portion 2 to furnish electrical shielding between the electrodeterminals.

As illustrated in Figures 3A and 4, each cavity 1 is sufiici'ently largeso that an individual pinclip 8 fits loosely therein, allowing bothexpansion of said pin clip on receiving a tube pin without beingrestricted by cavity I and a certain amountof free excursion within saidcavity. This permits a maximum amount of tube excursion beforestrain-producing forces are transmitted through the pin to the glassenvelope of the tube. on assembly, as illustrated by Figure 4, eachindividual pin clip 8 is inserted from the top of cavity I, terminal endI I first, and is-crimped below the bottom of the socket portion 2therein. I

to retain it loosely As shown in Figure 5, each individual pin clip 8 isshaped from a unitary strip of resilient metal having identical notchescut into opposing sides in the central portion [8 thereof. The upperedge of the strip is indented longitudinally in the form of a U, as at l(see Figure 5), and the sides of the upper portion of the strip are bentinto a generally cylindrical shape with the head of the cylinder l6being warped into the form of lips ll, of lesser inside diameter thanthe balance of said cylinder, so as to securely clamp an inserted pin ofa vacuum tube. The lower edge of the strip is rounded and a slotiscutinto the lower portion to enable the soldering of a connecting leadthereto.

As shown in Figure 4, each cavity 1 extending through socket or baseportion 2 comprises an upper cup portion 26, which is substantially D-shaped in horizontal cross section (as shown in Figures 3 and 3A), and aslot 22 communicating between the cup portion and the lower surface ofsocket portion 2, said slot 22 being a straight line in horizontal crosssection and in register with the fiat surface 24 of the said D-shapedcup portion. When a pin clip 8 is inserted into cavity 1, thecylindrical portion !5 is contained loosely within the cup portion 23while thenotched central portion N3 of pin clip 8 and the upper part ofthe terminal portion II are received within the slot 20, therebyallowing the lower part of the terminal portion l l of the pin clip 8 toextend below the under surface of the socket portion 2.- It; will bereadily seen that in assembly the insertion of pin clip 8 into cavity 1is easily accomplished without any forcing action.

A high center [2 is. provided on the socket portion '2 to support anelectron tube, at its base and thereby prevent the pins of the tube frombeing inserted completely within the socket portion 2; The high centerI2 also allows a tube to rock when subjected to vibrations and shocksand when it is being removed from a socket, as for replacement.Allowance is made for the pins to make good contact with the pin clips8, but since they are restricted from being completely inserted withinthe socket portion 2, any tube excursion will be accompanied by lessstrain-producing force on the glass envelope. This is due to theincreased lever arm between the tube envelope and the point where thepin is fastened to the pin clip 8. Heretofore, in standard tube sockets, the tube pins were inserted in rigid pin clips or through verysmall holes. Any shock or vibration of the tube socket thus caused thevibration or shock to be transmitted to the glass envelope of the tube.However, in our particular invention there is no such rigidityor'restriction. The pin clips 8 are loosely fitted in cavities 1. Eachtube pin is electrically connected to its pin clip 8 only at the innerperipheral surface of the lips i? thereof. Thus any vibration or shockto the tube base will not be transmitted through the glass envelope asreadily as in the structures heretofore mentioned, in which the tubepins were rigidly connected to a base socket. Further, each pin clip ofthe present improved socket is free to adjust its position to the tubepin being inserted as it is free to move laterally in the cavity l andit can pivot to a predetermined extent about the inner peripheralsurface of the lips H, the inner diameter of the cylinder it beinggreater than the outer diameter of the tube pin, except at the said lipsH, as already pointed out.

In the socket just described, the excursion Lil 4 limiter I and shield(not shown) are preferably of metal so as to act as an electricalshield. In addition however, the excursion limiter I should be highenough, and have an inside diameter of such size that it will allow avacuum tube a certain amount of lateral excursion, but will prevent anyexcursion beyond safe predetermined limits.

As already explained above, the present socket is so designed that eachof the pins of a vacuum tube is able to pivot relative to the pin clip 8into which it is inserted and each of said pin clips 8 is able to floatrelative to the socket portion 2. Hence a vacuum tube is free to undergoa certain amount of lateral excursion when subjected to shocks orvibrations. Such lateral excursion is further encouraged by the highcenter I2 of the socket portion 2, as it keeps the pins of a tube frombeing inserted too far into the pin clips 8 and it also acts as afulcrum about which the tube may rock.

This lateral excursion is desirable asit helps to absorb shocks andvibrations which otherwise would be transmitted to and injure the glassenvelope and/or the internal structure of a tube. It will be appreciatedhowever that, if the tube pins are pivoted beyond the point allowed bythe design of the pin clips 8 and socket portion 2, said pins will bebent and/or the glass envelope will be strained. The excursion limiter Iis therefore incorporated in the present socket to define limits withinwhich lateral excursion is safe and desirable, but beyond which suchexcursion would be likely to damage a tube.

Obviously, for the purpose aforesaid, the diameter of an excursionlimiter I will depend upon its height; the greater the height thegreater the permissible inside diameter. How-1 ever, as tubes areinserted and withdrawn by: hand, a certain amount of a tube shouldextend beyond the excursion limiter. Tests have dic-. tated that anexcursion limiter of about 4-inch is satisfactory for conventionalminiature tubes.

We have shown a combination of improve v ments in a tube socket, whichwill allow a desirable excursion of an electron tube, but which willkeep such excursion within safe limits and thereby will materiallyreduce strain on the glassenvelope thereof, when said electron tube ismounted in said tube socket. Tests have shown that this combinationeifects a substantial reduction in breakage of electron tubes by shockand vibration and in damage sometimes resulting when a tube is insertedor withdrawn from a socket.

Although we have shown and described aspecific embodiment of ourinvention, we are fully aware that many modifications thereof arepossible. Our invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

We claim: 1. In an electron tube socket having a base portion ofinsulating material, said base portion pro vided with a plurality ofcavities including a like plurality of resilient pin clips, said pinclips each" having an upper portion adapted to securely re sioned so asto loosely contain the constrictedportion of said clips, the combinationof means comprising a high center on said socket portion for fixing theextent to which a tube may be inserted into said socket and about whicha tube may be rocked, limiter means for limiting the amount of rockingof a tube about said high center after its insertion into said clips,and wherein the excursion limiter consists of a tubular member fixed tothe base, and extending upwardly therefrom, said tubular member havingan inner diameter larger than the upper diameter of the electron tubesurrounded by the tubular member, the difference in the said diameterspermitting a predetermined limit of lateral excursion of an electrontube operably positioned in said socket.

2. In an electron tube socket the combination of an insulating baseportion provided with a plurality of cavities, a plurality of resilientpin clips adapted to securely receive the pins of a tube, said clipshaving a constricted central portion, and a pin-gripping top portion,said cavities having an upper cup portion dimensioned so as to looselycontain the cylindrical portions and a narrow lower portion dimensionedto loosely contain the constricted portion of said clip whereby a tubeoperably positioned in said socket may rock, a raised portion in thecenter of said base portion to provide a fulcrum about which said tubemay rock; and means for limiting the extent to which a tube may berocked while positioned in said socket, said last-named means comprisingREFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,628,001 Schur May 10, 19271,767,139 Kirby June 24, 1930 1,767,690 Meuer et a1 June 24, 19301,771,094 MacFadden July 22, 1930 1,788,066 Reynders Jan. 6, 19312,269,605 Smith Jan. 13, 1942 2,398,626 Del Camp Apr. 16, 1946 2,444,048Keller June 29, 1948 FOREIGN PATENTS Number Country Date 559,579 GreatBritain Feb. 24, 1944

